#sintheta=sqrt(1-cos^2theta)#
or #sintheta=sqrt(1-(1/9)^2#
or #sintheta=sqrt(1-1/81#
or #sintheta=sqrt((81-1)/81)#
or #sintheta=sqrt(80/81)#
or #sintheta=sqrt80/9#==========Ans #2# #cosectheta=1/sintheta=9/sqrt80#=========Ans #3# #tantheta=sintheta/costheta=sqrt(80)/9-:(1/9)=sqrt80#=======Ans #4#